Some people have for historical reasons, developed a protective lack of transparency. This is a disconnect between appearance and experience. When some people seem not interested or engaged, they might be. People who appear sociable and agreeable might actually be otherwise inside.
The key is to assume nothing and check everything out. Good, simple questions can reveal a layer of feeling or intention just below what appears on the surface. With people whose non-transparency is deeply embedded in their narrative, trust sometimes creates space for them to be more congruent in their messaging. Whether or not we can actually influence their trust levels, we can always offer questions to invite more authentic expression.